Among renewable energy sources, wind energy generation has been noted as the most rapidly growing technology because it is one of the most cost-effective and environmental friendly means to generate electricity from renewable sources. Wind energy conversion systems convert the kinetic energy of the wind into electricity or other forms of energy. Wind power generation has experienced a tremendous growth in the past decade and has been recognized as an environmentally friendly and economically competitive means of electric power generation. This chapter describes the basics of the wind energy conversion system, its fundamental concept, basic components of a wind energy system, and system modeling and types of wind turbines.